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i955X Express Chipset Architecture For The Pentium EE 840


Infused with up to 22 PCI Express lanes on-board and the ability to configured for dual PCIe Graphics, with an optional bridge chip, the i955X Express and its companion ICH7 chipset is the next logical progression on Intel's chipset roadmap in support of their new dual core processors.  Here's a quick take on the i955X which our reference hardware is based upon in our upcoming performance benchmark tests.

Intel 955X Express Chipset Overview
Dual Channel DDR667, more PCIe expansion, SATA2 and support for Dual Core


The i955X is very much reminiscent of Intel's i925X or i915 chipsets, with a few notable exceptions.  First Dual Channel DDR-667 DDR2 DRAM is officially supported.  Although this has been available through many third party motherboard BIOS options with the current Intel chipset offering, this new official memory interface speed, coupled with a 1066MHz FSB, should offer a further performance boost and a bit more headroom even beyond with overclocking.

Interestingly enough, Intel is also showing capability to expand off the chipset's single X16 native PCI Express graphics slot, and with the help of another X16 bridge chip (which is not really a bridge but rather a PCI Express "fan-out" of sorts) the platform supports a dual X16 configuration for two PCI Express graphics cards.  There is no doubt, in addition to the nForce 4 SLI Intel Edition which you'll see here on HotHardware very soon, this expansion capability will also support NVIDIA's SLI Dual Graphics technology for the enthusiast and gaming community.  This is thanks in part to Intel and NVIDIA's recent cross-licensing agreement.


In fact, the system our staff tester received, was configured with dual PCIe graphics slots, with the second slot supporting a X4 PCI Express graphics configuration.  Theoretically, any X16 PCIe graphics card should be able to auto-negotiate down to a X4 config. Unfortunately, none of our current in-house PCIe graphics cards would function in SLI mode, most likely due to driver issues.

Finally, Intel's new ICH7 Southbridge that is coupled with the i955X now supports the SATA2 standard with up to 300MB/sec of bandwidth over its interface to a SATA II compliant hard drive.  In addition, the ICH7 has another two PCI Express links on it for further PCI Express peripheral expansion, now offering a total of 6 x1 links versus the ICH6's 4 x1 setup.

Test System Detail -


  • Intel Pentium Extreme Edition 840 (3.2 GHz)
  • Intel Pentium 4 570J (3.8 GHz)
  • Intel Pentium 4 540J (3.2 GHz)
  • AMD Athlon 64 4000+ (2.4 GHz)


  • Intel D955XBK 955X Express Motherboard
  • Intel D925XECV2 925XE Express Motherboard
  • ASUS A8N-SLI nForce4 SLI Motherboard


  • 1GB Micron DDR2-667 CAS 5 (2x512MB)
  • 1GB Corsair DDR2-533 CAS 3 Pro Series Memory (2x512MB)
  • 1GB Corsair DDR-400 CAS 2 Xpert Series Memory (2x512MB)


  • ATI RADEON X850 XT (Catalyst 5.3 Drivers)




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